This invention relates generally to improvements in inflatable boats and, more particularly, to a new and improved compartmentalized inflatable boat adapted for high speed applications.
People have long been fascinated by water and have constantly given thought to conquering and controlling it. Initially, hollow weeds or logs were bound together to enable the fording of rivers and the crossing of lakes. Eventually, inflatable boats incorporating air filled chambers formed of elastomeric or canvas materials were introduced for use as floatation devices. These inflatable boats have the advantages of increased mobility, because they can be deflated and stored in a relatively compact space, and economy, because of their lower production costs.
However, despite the aforedescribed advantages, these devices are generally not well suited for high speed aquatic usage. For purposes of illustration, high speed applications may be defined as including, but not limited to, speeds from about seven nautical miles per hour ("knots") to about thirty knots.
Because of their particular construction, i.e., a buoyancy chamber or a plurality of connected horizontally adjacent chambers defined by an elastomeric, canvas, or otherwise flexible material, inflatable boats do not generally have the fixed shape and structural integrity of conventional wood, fiberglass or metal formed boat hulls. As a result, inflatable boats may not be able to support the machinery necessary to move the boat at high speeds through the water. For this reason, to achieve high speeds, inflatable boats are generally towed behind another conveyance, i.e., a towing vehicle. However, when one side of the inflatable boat is subjected to a strong force, such as that exerted by a towing vehicle, there is an inclination of the air-filled hull. Concurrent with this inclination is a movement of the interior air mass within each chamber to the highest possible point, adversely affecting the shape and load carrying ability of the inflatable boat. Conventionally, a plurality of separate buoyancy chambers may be used to reduce this intra-buoyancy chamber airflow. Typically, however, the chambers may flex or pivot relative to each other, reducing the horizontal rigidity of the inflatable boat and increasing the drag of the boat within the water. As a result, conventional inflatable boats have not completely resolved the need to minimize intrabuoyancy chamber air flow while maintaining the horizontal rigidity of the inflatable boat hull.
Moreover, conventional boats attempt to minimize the magnitude of the force upon the towed inflatable boat by the use of conventional towing structures. Generally, this force is distributed by incorporating a plurality of towing seats or rings disposed peripherally upon the upper surface of the boat. A rope is passed through these tow seats and connected to a second tow-line extending from the tow vehicle. However, by this construction, the pulling on the latter tow-line affects portions of the inflatable boat differently, i.e., at each tow seat, distorting the inflatable boat in a multitude of directions. These multi-directional distortions contribute to the stresses applied to the inflatable boat and reduce the ability of the boat to follow the towing vehicle.
Skin frictional resistance is the drag of water upon the surface of the boat's hull, and it is generally the largest factor in the total resistance of the boat hull as it moves through the water. The skin friction of inflatable boats may be compounded by the effect of surface waves upon the boat's hull. Inflatable boats, because of their use of buoyancy chambers, generally ride higher in the water, i.e., have a minimum draft, and are more susceptible to wave action and drag.
Furthermore, as a result of conventional manufacturing methods, three-face welds, bonds or seams are typically incorporated into the construction of an air-filled boat. These welds or bonds are usually performed by high-frequency or resistance welding or bonding. However, because of the aforedescribed stresses and distortions, ruptures may occur at such welding seams.
As a result, there has been a significant, long existing need for an inflatable boat having a hull adaptable for high speed towing applications wherein the hull maintains horizontal rigidity, minimizes intrabuoyancy chamber air flow, avoids the use of three-face welding seams, and otherwise minimizes the drag or stress effects of high speed use. In addition, there has been a significant, long existing need for an inflatable boat having an improved towing seat or ring to distribute and diffuse the stresses exerted upon the boat by the towing vehicle. The present invention satisfies all of these needs.